This is Thailand, 10 satang (100 satang=1 baht), struck in aluminum-bronze with date BE2500 (=AB1957). The king depicted is Rama IX, Phra Maha Bhumibhol Adulyadej, which is the longest living reigning monarch: he became king in 1946 after his brother, king Rama VIII was found dead in his room while visiting his country.
Ref. Thailand 10 satang KM#79d